Plenty of mushrooms can be grown in a relatively small space. The essentials for mushrooms to survive are:

Fresh Air

12 Hours light cycle

Relative humidity from 80% upwards

The correct temperature

To accomplish this you will at least need a 6 X 3 meter grow house. a Well insulated Wendy House can work perfectly. Cover the inside with a layer of plastic, then a layer of 50mm isotherm and clad that with Newtech board. Paint the inside of your grow house with an anti-fungal paint. It is also advisable to have a drain and concrete slab in your grow house to be able to maintain a relative sterile environment.

When looking at the fresh air requirements for your grow space, most mushrooms need the air to be exchanged 4 times an hour. Work out the cubic meter space and purchase a fan than can push fresh air into your grow room at least four times per hour. Rather push air in than extract air, this will maintain a positive pressure in the grow space. Have a covered exhaust exit on the opposite side of the grow room.

For humidification I prefer using the ultrasonic humidifiers available from Green Thumb Hydro.

For lighting use LED strip lights, these will cost you less in the long term. Have them on a 12 hour timer switch.

For winter temperature control, have one or two wall mounted eco-heaters on a thermostatic switch to control the exact temperature.

To be successful at growing mushrooms, it is advisable to have a separate room for incubation, this room is dark, but also needs some fresh air as well as the correct incubation temperature.